title: Excitation wavelength dependence of primary charge separation in reaction centers from Rhodobacter sphaeroides.
abstract: The excitation wavelength dependence of the initial electron transfer rate in both wild type and mutant reaction centers from Rhodobacter sphaeroides has been studied between 840 and 920 nm as a function of temperature (10-295 K). The dynamics of primary charge separation show no resolvable excitation wavelength dependence at room temperature over this spectral range. A small variation in rate with excitation wavelength is observed at cryogenic temperatures. The low temperature results cannot be explained in terms either of a nonequilibrium model that assumes that the primary charge separation starts from a vibrationally hot state or a model that assumes a static inhomogeneous distribution of electron transfer driving forces. Instead these results are consistent with the concept that primary charge separation kinetics are controlled by the dynamics of protein conformational diffusion.
authors.affiliation: Biodesign Institute at Arizona State University and Department of Chemistry and Biochemistry, Arizona State University, Tempe, Arizona 85287-5201, USA.
authors.forename: Haiyu
authors.initials: H
authors.lastname: Wang
authors.forename: Su
authors.initials: S
authors.lastname: Lin
authors.forename: Neal W
authors.initials: NW
authors.lastname: Woodbury
mesh_terms: D004579:Electron Transport; D007700:Kinetics; D050505:Mutant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D012242:Rhodobacter sphaeroides / Q000737:chemistry*; D013696:Temperature
chemical_list: D050505:Mutant Proteins; D045322:Photosynthetic Reaction Center Complex Proteins